Summer population fluctuations, feeding, and growth of <i>Hydra</i> in an arctic lake1

Cuker, Benjamin E.; Mozley, Samuel C.

doi:10.4319/lo.1981.26.4.0697

Cited by 30 publications

(28 citation statements)

References 5 publications

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“…Feeding rates are particularly important in regulating Hydra population densities. Laboratory studies have shown that Hydra population growth rates are directly related to frequency of feeding (Muscatine and Lenhoff, 1965;Otto and Campbell, 1977) and in the field, Hydra population densities were shown to closely follow increases in zooplankton abundance (Cuker and Mozley, 1981). The feeding process is divided into a series of discrete steps: capture of prey with nematocysts, transport of prey to mouth, mouth opening, ingestion, digestion and ejection of exoskeleton.…”

Section: Feedingmentioning

confidence: 99%

Hydra, a model system for environmental studies

Quinn¹,

Gagné²,

Blaise³

2012

Int. J. Dev. Biol.

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Hydra have been extensively used for studying the teratogenic and toxic potential of numerous toxins throughout the years and are more recently growing in popularity to assess the impacts of environmental pollutants. Hydra are an appropriate bioindicator species for use in environmental assessment owing to their easily measurable physical (morphology), biochemical (xenobiotic biotransformation; oxidative stress), behavioural (feeding) and reproductive (sexual and asexual) endpoints. Hydra also possess an unparalleled ability to regenerate, allowing the assessment of teratogenic compounds and the impact of contaminants on stem cells. Importantly, Hydra are ubiquitous throughout freshwater environments and relatively easy to culture making them appropriate for use in small scale bioassay systems. Hydra have been used to assess the environmental impacts of numerous environmental pollutants including metals, organic toxicants (including pharmaceuticals and endocrine disrupting compounds), nanomaterials and industrial and municipal effluents. They have been found to be among the most sensitive animals tested for metals and certain effluents, comparing favourably with more standardised toxicity tests. Despite their lack of use in formalised monitoring programmes, Hydra have been extensively used and are regarded as a model organism in aquatic toxicology.

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Section: Feedingmentioning

confidence: 99%

Hydra, a model system for environmental studies

Quinn¹,

Gagné²,

Blaise³

2012

Int. J. Dev. Biol.

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“…in the summer. Some authors found that Hydra prefer smaller size prey, such as the representatives of Bosmina genus (Dodds and Cole, 2007) or Cyclops (Cuker and Mozley, 1981). Hydra species are classified as valuable study organisms, especially as predatory invertebrates in trophic relations, studied also in matter and energy transport through various macrophyte species in the lake ecosystem which support a diverse composition and abundance of invertebrate fauna, depending on the morphology of leaves, production of allelopathic compounds and depending on whether they are submerged, floating or emerged plants (Cheruvelil et al, 2002;Mc Abendroth, 2005;Bogut et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Phytophilous Fauna of a Small and Artificial Urban Lake

Krajina¹,

Bogut

Čerba

et al. 2017

Croatian Journal of Fisheries

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Phytophilous community on Myriophyllum spicatum was studied in a small artificial urban lake in the city of Osijek (eastern Croatia), during the spring and summer season in 2010. In the eutrophic conditions, macrophyte stands were well developed and in the formed periphyton representatives of the following invertebrate taxa were found: Hydrozoa, Nematoda, Gastropoda, Cladocera, Copepoda, Insecta larvae - including families Chironomidae and Coleoptera. They displayed differences in temporal abundance patterns. Two separate phases in macrophyte colonization with differences in invertebrate composition and abundance were recorded. Insect larvae, particularly Chironomidae, were most abundant in the first phase, through the spring period, and Hydra oligactis (brown hydra) was most abundant in the second phase, i.e. summer period. Concurrently, microcrustacean abundance declined towards the end of the summer. Results of the analyses indicated that water temperature and perihyton biomass were the variables exerting the main influence on the invertebrate assemblage, while interestingly, macrophyte size and biomass were negatively correlated with most of the fauna abundance. On the other hand, brown hydra was negatively correlated with all other invertebrate taxa, except gastropods. Larger surface of submersed macrophytes is the main parameter supporting the increase of invertebrate abundance due to providing protection from predators and growth for periphyton, an important food source for these phytophilous organisms. Macrophyte length was positively correlated with Hydra abundance, while Chironomids were more influenced by periphyton biomass. These organisms can indicate water quality conditions and a potential increase in primary and secondary production.

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“…It has also been reported that hydras are preyed by platyelminthes (Hyman 1940, Kanaev 1969, despite the observation that small platyhelminths avoid contact with these cnidarians (Slobodkin & Bossert 2001). Cuker & Mozley (1981) It was apparent that the gastropods covered the hydras with mucus, thereby protecting themselves from the nematocysts. Therefore, the presence of nematocysts most likely prevented the consumption of hydras in the present study.…”

Section: Discussionmentioning

confidence: 99%

A search for predators and food selectivity of two native species of Hydra (Cnidaria: Hydrozoa) from Brazil

Massaro

Negreiros

2013

Biota Neotrop.

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Abstract:The Hydra is the most common representative of freshwater cnidarians. In general, it is found in freshwaters on every continent, with the exception of Antarctica. The aim of the present study is to gather biological and ecological data on aspects of two species of Hydra native to Brazil: Hydra viridissima and Hydra salmacidis. Predation and food selectivity experiments were performed to assess the possible predators and the prey preferences, respectively, of the two species. The results indicate that the two species of Hydra were not consumed by any of the predators that were tested, which are typical predators of invertebrates in freshwater: nymphs of Odonata Anisoptera and the phantom midge larvae of Chaoborus sp. (Insecta), adults of Copepoda Cyclopoida (Crustacea) and the small fish Poecilia reticulata. It was observed that the smaller Hydra, H. viridissima, positively selected the nauplii and copepodites of calanoid copepods and small cladocerans and rejected large prey, such as the adults of calanoid copepods and ostracods. The larger H. salmacidis, besides the nauplii and copepodites of the calanoid copepods and small cladocerans, also positively selected the large adults of the calanoid copepods. It can be concluded that both H. viridissima and H. salmacidis are most likely preyed on little or not preyed on at all in many freshwater bodies, as they are top predators in the food chain. At the same time, they are efficient predators, and a positive relationship was observed between the prey size and the Hydra species size. Food selectivity was related to prey size as well as other prey characteristics, such as carapace thickness and swimming efficiency. Keywords: Hydra viridissima, Hydra salmacidis, predation, prey selection, feeding.MASSARO, F.C, NEGREIROS, N.F. & ROCHA, O. Potenciais predadores e seletividade alimentar de duas espécies de Hydra (Cnidaria: Hydrozoa) nativas no Brasil. Biota Neotrop. 13(2): http://www.biotaneotropica. org.br/v13n2/pt/abstract?article+bn00713022013Resumo: As hidras são os representantes mais comuns dos cnidários de água doce. Em geral, estes organismos são encontrados em todos os continentes, exceto na Antártica. O presente estudo teve como objetivo obter informações mais aprofundadas sobre aspectos biológicos e ecológicos de duas espécies de Hydra nativas no Brasil, Hydra viridissima e Hydra salmacidis. Foram realizados experimentos de predação e seletividade alimentar para se determinar, respectivamente, os potenciais predadores e as presas preferenciais destas duas espécies. Os resultados indicaram que as duas espécies de Hydra não foram consumidas por nenhum dos predadores testados, os quais são usuais predadores de invertebrados em águas doces: ninfas de Odonata e larvas de Chaoborus sp. (Insecta), adultos de Copepoda Cyclopoida (Crustacea) e peixes da espécie Poecilia reticulata. Observou-se que H. viridissima ao se alimentar selecionou positivamente as fases jovens de copépodos calanóides e os pequenos cladóceros, e selecionou negativamente as presas grandes...

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Summer population fluctuations, feeding, and growth of Hydra in an arctic lake1

Abstract: During 1977, the population

Cited by 30 publications

References 5 publications

Hydra, a model system for environmental studies

Hydra, a model system for environmental studies

Phytophilous Fauna of a Small and Artificial Urban Lake

A search for predators and food selectivity of two native species of Hydra (Cnidaria: Hydrozoa) from Brazil

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